Electromagnetic devices



Jan. 6, 1959 F. E. ROMMEL ETAL ELECTROMAGNETIC DEVICES 2 Sheets-Sheet 1 Filed 001;. 17. 1955 /NVENTO/P nw-mal ATTORNEY Jan. 6, 1959 F. E. ROMMEL EIAL ELECTROMAGNETIC DEVICES 2 Sheets-Sheet 2 Filed Oct. 17. 1955 A 770R NE) 7 air ELECTROMAGNETKC DEVICES Application October 17, 1955, Serial-No. 540,911

Claims priority, application Great Britain November 3, 1954 11 Claims. (Cl. 317- 176) This invention relates to electromagnetic devices such as relays having a vibratory armature suspended with relation to a magnetic structure. and it is particularly con cerned with the suspension or vibratorymounting systems of such armatures. The mounting of such armatures with precision becomes more diflicult the smaller the dimensions of the device are and, in fact, the present invention is particularly applicable to the mounting and suspension of the armatures ofsmall polarised electromagnetic relays which are often referred to as miniature relays.

The invention is, in fact, concerned with armature suspension systems which comprise a pair of-resilient suspension arms fixed to the armature and respectively extending from the armature on opposite sidesand lying substantially in or parallel to the general planeof the armature. It has been usual to clamporanchor such arms to the frame of the device and to set the armature into positionby the use of packing. strips or shims placed in position in contact with the said arms.

The main object of the present invention is toprovide an adjustable mounting of the resilient suspension arms such that the armature can be readily adjusted according to the principal modesof adjustment without disrnantli-ng the device. Thus, in particular, the invention aims. at providing for bodily or translation adjustment of the armature at right angles to its own general plane to provide for adjustment of the airgaps on eitherside between the armature and the cooperating faces of the stationary magnetic structure; also at permitting, of tiltingof the armature about its longitudinal axis and at allowing also of tilting about its axis of vibration to enable the armature to be set with its general plane parallel to those of the cooperating opposite faces of the stationary magnetic structure.

To provide for such adjustments, according to the present invention, the resilient suspension. armsare carried by corresponding supports having seating surfaces which permit the arms to be tilted aboutan axis parallel to the axis of vibration of the armature onadjustment of tilting means, the supports being capable of adjustment separately so as to effect tilting of the arm about an axis parallel to the longitudinal axis of the armature and together so as to effect translation of the armature relatively to the frame of the device. Thus, if the two supports are adjusted by the same amount in the same direction, the armature and its suspension are moved bodily at right angles to its general plane and can thereby be set centrally in the gap between two opposite pole faces of the stationary magnetic structure. The seating surfaces on the supports are shaped and arranged so that the suspension arms can slightly tilt on them in all directions so that if one support is adjusted more than the other one, the general plane of the armature is tilted about its longitudinal axis so that transverse lines on the armature can be made parallel to the said' stationary polefaces; finally by adjusting the tilting means, the arms 'are rocked about the axis of vibration of the armature so ire that its general plane is parallel to those of the stationary pole-faces. Preferably the arms are retained in position with respect to the frame by a single retaining member which constitutes the tilting means. This retaining member may be in the form of a bifurcated plate, the two prongs of which press on the end parts of the arms and the tilting movement of which is adjusted by a retention member attached to the frame of the device.

In an actual example of construction, the supports are in the form of a pair of small screws which are threaded in side members of the non-magnetic frame ofa polarised relay in such positions as to register respectively with holes in the opposite spring suspension arms of a movingiron armature. The screws are pointed at their ends with the points shaped to afford seatings for the suspension arms, the holes in which are of such a size to allow the arms to rock to a limited extent on the seatings in all directions.

In order that theinvention may be clearly understood and readily carried into effect, an example of the invention applied to a miniature polarised relay will now be more fully described with reference to the accompanying drawings, in which:

Figure l is a perspective view of a relay according to patent application Serial No. 513,381 of 1955 with a suspension system according to the present invention;

Figure 2 is a plan of the same; while Figure 3 is a side elevation of Figure 2;

Figure 4 is a plan to an enlarged scale showingthe front end of the armature and its suspension but with the upper permanent magnet and the contact assembly omitted;

Figure 5 is a vertical section taken on the line VV in Figure 4; and

Figure 6 is an elevation of the central part of the relay according to Figure 3 but with certain portions omitted to show the clamping together of the component parts.

The. relay illustrated is as disclosed in patent application SerialNo. 513,381 of 1955 and briefly is mounted on a frame plate 1 having side members 2. A spacing bar 3 of non-magnetic insulating material extends across the frame plate 1 to which it is secured by a pair of bolts 4. As seen in Figure 6, a pair of soft iron pole-pieces 5 have accurately finished inner surfaces bedded on to corresponding surfaces of the spacing bar 3 and then a pair of permanent magnets 6 each has an accurately finished face on its inner surface resting on a flux-concentrating pole-piece 7 of soft iron which, in turn, rests on a corresponding accurately formed face on the outer surface of the respective pole-piece 5. These parts are clamped together in position by a single central bolt 8. The actuating orsignals winding 9 is carried on and embraces a rearward extension of the upper soft iron pole-piece 5 as best seen in Figure 3. The permanent magnets 6 have like poles at the armature 10 and if these are north poles as indicated in Figure 6, the flux leaving both of the polepieces 11 passes for some distance along the armature 10 and emerges from both sides passing into the soft iron pole-pieces15 along to the flux concentrators 7 and back to the magnets 6. These parallel paths for the polarising flux are shown by the continuous line 12. The path of the signals flux is indicated by the broken line 13. Thus the magnetic circuit of the relay is a divided magnetic circuit as disclosed in U. S. Patents 1,826,990, 2,412,123 and 2,559,399.

The lower permanent magnet 6, as seen in Figures 3 and 5, extends up between the side members 2 of the frame 1 andthe armature 10 lies at a somewhat higher level. The armature lilconsists of two strips of soft magnetic material riveted together with the resilient strip 1d forming the suspension arms clamped between them.

The result of this, as seen from Figure 6, is that the armature 10 tapers somewhat as it extends between the polepieces 5 giving a shortened airgap and increased flux density at the right-hand tips of the pole-pieces 5. t

The right-hand end of the armature is offset as seen at in Figure 4- and, near its end, bears an actuating ball 16 of insulating material. This ball 16 actuates the upper and lower movable contacts of the contact as sembly seen most clearly at the right-hand side of Figures 1 and 3. These movable contacts are carried on springs 17 which are bent over almost horizontally so that a certain amount of rubbing occurs when they strike the stationary contacts 18. The contact assembly is mounted on a plate of insulating material 1 9 by a screw 20 and the plate 19 is secured to the relay frame 1 by a screw 21. This contact assembly, however, does not form part of the present invention.

The adjustable armature suspension according to the present invention is, in the example illustrated, arranged as follows. The suspension strip 14 clamped by the armature 10 as already mentioned, has the ends of its arms somewhat enlarged as seen at 22 (Figure 4) and the ends are perforated so as to fit over a shouldered bush 23 at each end. The bushes 23 have bores which are countersunk at their lower ends to rest on the conical upper ends of a pair of screw-threaded studs 24 which are adjustably screwed into the side members 2 of the relay frame 1. Each bush 23 is engaged and held down by one perforated arm 25 of a plate 26 which bears on the resilient suspension strip 14 at each of its ends. The plate 26 is arranged to tilt about the conical upper ends of the studs 24 and to the effect that tilting, a screw 27 is screw-threaded into the forward part of the relay frame 1 and the head of the screw 27 presses on the forward end of the plate 26 which has an aperture 28 through which the shank of the screw 27 passes. It will be seen from Figure 4 that the extension 15 of the armature It is shaped so that it is cleared by the screw 27. The arms 25 are pressed down on to the respective ends of the suspension strip 14 by two bearers 29 (Figures 1 to 3), the front ends of which press on the arms 25. The bearers 29 are each clamped on top of the spacer bar 3 by one of the bolts 4. Each stud 24- has a screw-driver slot 30 at its lower end so that it can be screwed up or down in the side member 2 of the relay frame 1. If one of the studs 24 is adjusted more than the other, the arm-ature 10 is tilted about its longitudinal axis. If the screw 27 is adjusted without moving either of the studs 24, the plate 26 is rocked about the upper ends of the studs 24 and the armature 10 is tilted about its axis of vibration. Finally, if the two studs 24 are adjusted by equal amounts in the same direction and, at the same time, the screw 27 is also adjusted to a suitable extent, the armature 10 can be moved up or down bodily and thereby centralised between the soft iron pole-pieces 5.

Although the plate 26 engages the under surface of the head of the screw 27 resiliently and firmly, the screw 27 may be furnished with a nut below the plate 26 and the nut may be screwed up to hold the plate 26 positively against the head of the screw 27 to prevent them separating due to the action of inertia of the moving parts under conditions of impact or high acceleration.

Although the invention has been shown as applied to a polarised electromagnetic relay having magnetic components according to patent application Serial No. 513,381 of 1955 it is applicable widely to electromagnetic relays and similar vibratory electromagnetic devices having various arrangements of their magnetic structures.

We claim:

1. An electromagnetic device comprising a frame member, a magnetic structure mounted on said frame member and presenting a working air gap between a pair of pole pieces, an armature mounted to vibrate in said air gap and about a vibrational axis extending transversely of the armature, a pair of resilient suspension arms attached to said armature and extending from opposite sides thereof along said vibrational axis, a retaining member pressing on said arms to retain them in position with respect to said frame member, means offset from said vibrational axis for turning said retaining member with respect to said frame member whereby said armature may be tilted about an axis parallel to said vibrational axis, and two screw-threaded studs, each of said studs being adjustably fitted in said frame member and being formed with a conical end, said conical end serving as a bearing surface on which a corresponding one of said arms is carried.

2. An electromagnetic device according to claim 1, including two bushes, each of said bushes clamping said retaining member to the end of one of said arms and being formed with an internal annular surface engaging a corresponding one of said conical ends.

3. An electromagnetic device comprising a frame member, a magnetic structure mounted on said frame member and presenting a working air gap between a pair of pole pieces, an armature mounted to vibrate in said air gap and about a vibrational axis extending transversely of the armature, said armature comprising two strips of soft magnetic material clamped together, a resilient suspension strip clamped at its centre between said two strips and offset from said air gap so that said armature tapers in the neighborhood of said air gap, said suspension strip at its ends extending from opposite sides of said armature, two bushes secured respectively to the ends of said suspension strip and each being formed with a cylindrical wall defining an opening perpendicular to the surface of said suspension strip, two screw-threaded studs adjustably fitted into said frame member and each of said studs being formed with a conical end on which bears one of said walls, a retaining plate having two separate prongs secured to said suspension strip by said bushes, and a screw fitted into said frame member and adjustably holding said retaining plate in relation to said frame member.

4. An electromagnetic device comprising a frame member, a magnetic structure mounted on said frame memer and formed with parallel facing pole faces defining a working air gap between a pair of pole pieces, an armature mounted to vibrate in said air gap and about 21 vibrational axis lying outside said air gap and substantially parallel to said faces, a pair of resilient suspension arms attached to said armature and extending from opposite sides thereof along said vibrational axis, means mounted on said frame member for tilting said arms about an axis parallel to said vibrational axis, a single pair of separate, spaced, separately adjustable screw-threaded studs, each of said studs being carried by said frame member and carrying one of said arms, and each of said studs having one of its ends shaped as a conical bearing surface, said bearing surface lying between said arm and said frame member whereby each of said arms is carried by said frame member through said bearing surface and is moved relatively to said frame member on adjustment of said stud to alter the position of said armature with respect to said faces.

5.,An electromagnetic device according to claim 4, wherein each of said studs is screwed into said frame member with its conical bearing surface carrying a corresponding one of said arms.

6. An electromagnetic device comprising a frame member, a magnetic structure mounted on said frame member and presenting pole faces on a pair of pole pieces, an armature arranged to face said pole faces and mounted to vibrate about a vibrational axis extending transversely of the armature whereby on vibration said armature moves to alter the distances between said armature and said pole faces, the armature mounting comprising a pair of resilient suspension arms attached to said armature and extending along said vibrational axis, and a retaining member by which said arms are held, said retaining member being movably mounted on said frame member, and at least three spaced screw-threaded members extend- 3 5 u mg between the frame and retaining member for independent adjustment for tilting said arms about an axis parallel to said vibrational axis and for moving each of said arms transversely of said vibrational axis, whereby said armature may be brought into the desired relationship with said pole faces.

7. A device according to claim 6, two of said screw threaded members being spaced apart on a line parallel to said vibrational axis, whereby the said tilting of said arms about an axis parallel to said vibrational axis is effected by adjustment of a third screw-threaded member.

8. A device according to claim 7, the said two screwthreaded members being adjustably screwed into said frame member and being provided at their ends with bearing surfaces, said retaining member pressing substantially directly on said bearing surfaces, whereby adjustment of said third screw-threaded member causes tilting of said arms about an axis substantially coincident with said vibrational axis.

9. A device according to claim 8, and also comprising resilient means carried by said frame and pressing said retaining member towards said bearing surfaces.

10. A device according to claim 9, said third screwthreaded member being adjustably screwed into said frame member and being provided with a head having a bearing surface, said retaining member being pressed against the bearing surface of said head by said resilient means.

11. A polarised electromagnetic relay comprising a frame member, a signals magnetic structure mounted on said frame member and presenting a working air gap 6 between two fiat parallel pole faces, a flat elongated vi bratory armature mounted to vibrate in said air gap and about a vibrational axis extending transversely of said armature and lying in the general plane of said armature and perpendicular to the length of said armature, a pair of resilient suspension arms attached to said armature and extending along said vibrational axis, a retaining member holding said arms and movably mounted on said frame member, and three screw-threaded members adjustably screwed into said frame member and bearing against the retaining member for controlling the angular and bodily position of said retaining member, whereby adjustments of the said screw-threaded members bring ,the armature parallel to said pole faces and midway between them.

References Cited in the file of this patent UNITED STATES PATENTS 688,554 Skirrow Dec. 10, 1901 841,215 Andrews Jan. 15, 1907 902,105 North Oct. 27, 1908 1,333,247 Cummings Mar. 9, 1920 1,728,840 Strawostrand Sept. 17, 1929 2,458,247 Bryan Jan. 4, 1949 2,515,771 Hall July 18, 1950 2,689,279 Noregaard Sept. 14, 1954 FOREIGN PATENTS 1,006,837 France Ian. 30, 1952 846,737 Germany Aug. 18, 1952 

